Variable stroke tool



May 5, 1931. H. c. Gus-rAFsoN VARIABLE STROKE TOOL Filed May 21. 1928 4 Sheets-Sheet 1 5MM/awww@ A @krom/w13 May 5, 1931- H. c. GUsTAFsoN 1,804,21

VARIABLE STROKEPVTOOL Filed May 2l. 1928 4 Sheets-Sheel' 2 25? 5 ff 44 Z694 429 .30

it, 'ef l willi-ll May 5, 1931 H. c. GUsTAFsoN 1,804,216

VARIABLE STROKE TOOL Filed May 21, 1928 4 Sheets-Sheet 3 May 5, l931- H. c. Gus'rAFsoN 1,804,216

VARIABLE STROKE TOOL Filed May 2l. 1928 1 Sheets-Sheet 4 Patented May 5, 1931 f UNITED STATES PATNT OFFICE HJALMER C. GUSTAFSON, F DENVER, COLORADO, ASSIGNOR TO GARDNER-DENVER COM- PANY, OF DENVER, COLORADO, A. CORPORATION 0F DELAWARE VARABLE STROKE TOOL Application iled May 21, 1928. Serial No. 279,370.

The present invention relates more particularly to rammers and like structures. In foundry work it is sometimes desirable when packing sand around a core to use short and less powerful strokes than when packing around the edge of the mold where firmness is essential.

The object of the present invention is to provide a tool of this character, in which the stroke of the piston can be varied. While particularly intended for ramming sand in molds, obviously its use is not thus limited,`

but the tool may be employed for other purposes, such as backll tamp-ing, clipping and in fact any place where a variable stroke tool is desired. v

A preferred embodiment of the invention is illustrated-in the accompanying drawings, wherein:

Figurev 1 is a view partially in elevation and partially in section.

Figure 2 is a longitudinal sectional view on an enlarged scale through the rear end portion of the cylinder and associated mecha.- nism. l

Figure 3 is a view similar to Figure 2, but showing the piston at the rear end of its stroke and the mechanism arranged for a short stroke operation.

Figures 4 and 5 are cross sectional views respectively on the lines 4 4 and 5 5 of Figure 3.

Figure 6 is a detail longitudinal sectional view on the line 6-6 of Figure 3.

Figure 7 is a cross sectional Vview on the line 7--7 of Figure 2.

Figure 8 is a side elevation of the rear cylinder head.

Figure 9 is a view of the various parts which constitute the distributing valve mechanism.

Figure 10 is a detail longitudinal sectional view of the cylinder.

' Figure 11 is a detail view partially in section of a modification of the means for holding the rear head against detachment. Figure 12 is a perspective view of the rea-r head.

Figure 13 is a detail view in elevation of a modiied form of means for holding the controlling sleeve in its different positions.

Figure 14 is a sectional view on the line 14-14 of Figure 13.

Figure 15 is a view similar to Figure 14, but

showing a modied form of holding means for the controlling sleeve.

Figure 16 is a view in elevation of a modi- 5 fled form of structure for holding the rear head against turning.

Figure 17 is a sectional view on theline The piston chamber 23 opens through the f rear end of the cylinder 18, and detachably iitted into said rear end is a valve casing 25 having a flange 26 abutting the rear end of the cylinder. The front end of the valve casing 25 has an opening 27 therethrough afording communication between the' interior of the casing and the rear end of the piston chamber 23. In rear of said opening 27 there is Jformed an internal annular motive fluid supply groove 28 and in rear of said groove 28 there 1s Jformed an annular internal distributing groove 29. This distributing groove is in communication by a passageway 30 with the front end of the piston chamber 23 V(see Figure 10). Behind the distributing` groove 29 there is formed an internal annular exhaust groove 31, from which an exhaust port 32 opens through the cylinder wall, and behind said exhaust groove there is another groove 33 into which opens a passageway 34 that opens at 35 into the interior of the piston chamber 23. Behind the groove 33 and inY the rear end of the valve casing 25 is formed an internal annular trip groove 36 of larger diameter than the above mentioned grooves. From the front portion of said groove 36, a bleed port shown in dotted lines at 37 in Figure 3 opens to atmosphere.

The rear end of the valve casing 25 is furthermore provided with a recessed seat 3S, in which is fitted the flange 39 of a bushing 40 that extends into the rear end of the valve casing 25 in spaced relation to the walls thereof. This bushing is engaged by a packing gasket 4l preferably held in a cupped sa eway for. the fluid.

n the casing 25 is a reciprocatory tubular distributing valve designated 43. This valve slidably lits within the valve easing and has its rear. end slidably fitting on the bushing 40. Obviously therefore motive fiuid is supplied tothe interior of this valve through said bushing 40. rlie rear end of the valve isprovided with a trip flange 49 operating in the trip groove 33. It is provided with a closed front end 50 that is movable to and from a position to plug the open end 2i of' the valve casing. It is further provided at its front end with lateral supply7 ports 5l opening-into the supply groove 23. Behind these ports the exterior of the valve is reduced, as shown at 52 to afford communication between the supply groove 28 and the distributing groove 29wlien the valve is in its foremost position or as shown in Figure 2. Whemhowever, the valve is in its rear position and the opening 2T is uncovered', then communication between `the supply groove 28l and the distributing groove 29 is cutolf, asshown in Figure 3. The valve further is provided behind the reduced portion 52 with another reduced portion 53 that establishes andfcutsoilk communication between the exhaust roove 31 and the groove 33, accordingly as t ie valve is in one'or the other position, illustrated in Figures 2 and 3.

The cylinder 18 is provided with a front exhaust port 54 and a rear. exhaust port 55. These exhaust ports are successively covered and uncovered by the piston 22 during itsv reciprocation.` Leading from the piston chamber' 23 at a point in rear of the front exhaust port 54 is a` trip passageway 5,6 that opens into the rear portion of the trip groove 3G and behind the valve flange 49.

Another and shorter trip passageway 5'? alsov opens into said trip groove 36 behind the valve flange 49. At the front end of said trip passageway 57 and really forming al part of the saine under certain conditions is a port 58 that opens into the piston chamber 23 at a point behind the rear exhaust port 55 and in rear of the front end of the trip passageway 56. Rotatably mounted on the cylinder is a controlling sleeve 59 that extends over the ports 55 and 58. This sleeve is provided with a port 60 adapted to register with the rear exhaust port lt is also provided with a channel (il affording communication between 'the' port 5S and the shorttrip passageway 57 when port 60 alines with the port 55.

The sleeve 59 has its front end abutted against a flange formed on the cylinder. lts rear end is abutted against by a spring 63 which as shown in Fit( ire l engages a ratchet ring 64 that engages ratchet teeth 65 formed on the 'liront end of the skirt 44 of the rear head 43. rlhe ring 64 as shown in Figure 5 is provider .vit.A lreys engaged in grooves 6T in the cy ider i3 and thus is held against rotation. lfhe movement of the controlling sleeve liinited by an outstanding pin 68 Figure l) which engages in a slot 69 formed in the sleeve, the ends of the slot being enlargedv to receive the piu 63 and thus holding the sleeve against accidental rotation. (This is shown in detail in the modified form of struct illustrated in Figure ll.)

Tim I M- `f f 'd l 'tl "l lt it it i4 i.J pioviciec wi i an ex iaus port TU iii communication with the exhaust port 32 tlirough an annular groove 70a and said exhaust port YO opens imo an annular groove 7l. The rear portion of the trip groove 35 l the trip passageways 5G and 57. This trip port (see Figure 3) opens into an annular groove i3 foi-ined in the interior of the skirt 44 oi the rear bead 43 and this groove in turn is in communication by means of a port 74 with an annular groove 275 located in rear of the groove 71'." rEhe two annular grooves 7 l and T5 are covered by a rotatable ring 76 which is provided at one point with an enlargement 77, the interior '78 constituting an exhaust port opening forwardly, as sho-wn at 79 to atmosphere and permitting the escape of motive fluid from the grooves 7l and 75, to atniosijihere. By turning this ring the point of exhaust or escape can be placed at any point desirable to the operator.

lt believed that the operation of the structure can now be made clear. lilhen a long stroke operation of the piston 22 is desire l. the controlling sleeve 59 is turned so that the exhaust port is closed and communication is cut off between the port 58 and the short tripk passageway 57. lf now air or motive fluid is supplied to the distributing valve, assuming the valve in its rearward position as shown in Figure 3. an( the piston at the rear end of'its strolre7 the air wil pass through the interior ot the valve out of the ports 51, through the supply passageway 28 and opening 2'?, -into the piston chamber 23 behind the piston. :eiaust in advance of the piston takes place through the port As vthe piston uncovers the port 53 no action will friiD e has a oleed port T2 of less diameter thanv llU take place because said port is out of communication with the passageway 57 and therefore the piston continues its advance until it uncovers the trip passage-way 56, thereby admitting motive fluid from behind the'piston through said passageway and behind the Harige 38 of the valve. The area of said flange being great enough to overcome the pressure against the front end of the valve, the valve is shifted to its forward position or to the position shown in Figure 2. When this position is taken the front end of the valve plugs the opening 27 and cuts off further supply of ymotive fluid to the rear end of the piston p chamber 23, but at the same time communicationis oiened between the su a l Oroove 28 and the distributing groove 29. The motive fluid therefore finds its way through the passageway 30 to the front end of the piston 'chamber 23, and operating against the front the frontend of the valve is suficient to force said valve rearwardly, the pressure on the flange 36 in the meantime being reduced by the escape of motive fluid through the -bleed.. port 74. The ports are now in the posi- `tion first described.

1When it is desired to shorten the stroke of the tool it is only necessary to turn the controlling sleeve 59 until the exhaust port 55 w is opened by the port 60 in said sleeve and the port 58 is brought into communication with the short trip passageway 57 by the channel 61, as shown in Figure 3. Vhen this occurs, the trip passageway 56 becomes idle ben cause as soon as the piston 22 uncovers the port 5S, fluid under pressure will pass through the short trip passageway 57 and shift the valve as above described. The exhaust port 55 now becomes active to permit the initial escape of motive fiuid from behind "the piston on the rear stroke thereof, while the exhaust port 54 still serves to permit the escape of iiuid in advance of the piston during the front stroke. Otherwise the operation is the same, except that the length of i the stroke is reduced.

Various modifications of the structure may be employed. Thus in Figure 11, the means for holding the rear head here desig- K nated 43a is accomplished by means of a key 39 engaged with the head and with the cylinder i865. This key is overlaid by a ring 81 against which the spring 63 bears. y The ring 81 is provided with projections S2 engaging in notches 83 formed in the flange 84 of the head 43a. The controlling sleeve 59a as shown is provided with the usual slot 69a engaged by a pin 68athat limits the rotation of said sleeve 59a. positioning movement of the controlling sleeve may be accomplished in variousways. Thus in Figures 13 and 14 the sleeve here designated 596 is provided with spaced openings 85 and a spring-pressed plunger 86 carried by the cylinder 18?) is adapted to engage in either of said openings 85. Y

ln Figure 15 a still diferent form of construction is shown. Here the controlling sleeve 590 is provided with an internal channel 87 of limited length and in said channel is engaged a springpressed friction limiting and holding flange 88.

As shown in Figures 16 and 17, the means for holding the rear head against rotation can be further varied. Thus, thereinV shown is a portion of the cylinder 18d and the head is shown at 43d threaded on the cylinder.V

Engaged in a socket 89 of the cylinder 18d is a key 90 that engages in a notch 91 in the head 43d. The spring shown at 63d overlies a portion of the key and holds it in place, this spring bearing against the controlling sleeve, a portion of which is shown at 59d.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without further description and it will be understood thatk various changes in the size, shape, proportion and minor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

What I claim, is: f

1. In a variable stroke fluid operated tool, the combination with a cylinder having a piston chamber and a piston operating in the chamber, of means for causing the piston to have strokes of dierent lengths including exhaust ports for the piston chamber opening from the piston chamber at different distances from the valve and covered and uncovered by the piston, an automatic distributing valve, a plurality of trip passageways leading from the piston chamber at diderent distances from the valve and extending to the valve and covered and uncovered by the piston, and means forvclosing and opening the exhaust port and the trip passageway that are closer to the valve.

2. In a variable stroke fluid operated tool, the combination with a cylinder having a piston chamber and a piston operating in the chamber, of means Vfor causing the piston to have strokes of different lengths including exhaust ports opening from the piston chamber at different points and covered and uncovered by the piston, an automatic distributing valve, a pluralityof trip passageways leading from the piston chamber at different points to the valve and covered and uncov- This limiting or.

sul

ered by the piston, andj a sleeve rotatably mounted on the cylinder and having means for closing and. opening one of the exhaust portsl and' oneof the trip passageways.

3; Ina variablestreke fluid operated tool, the combination with a cylinder having a piston: chamber andI a reciprocatory piston operating therein, of an automatic valve for distributing fluid to the. piston having a pressure surfacesaid piston chamber having av front and a rear exhaust port opening at dilierent point-s and successively covered and uncovered by the pistom trip passageways tothe pressure surface of the distributing valve and having front and rear inlet ports opening into the piston. chamber and successively covered and uncovered by the piston, and asleeve rotatably mounted on the cylinder and having a port movable into and out of alinement with the rear exhaust port and a passageway that is movable into and out of a position to establish communication With the rear inlet port and one of the trip passageways.

4f.y In a variable stroke fluid operated tool, the combination with a cylinder having a. piston chamber, of a rear head for the cylinder threaded thereon, a piston in the pistou chamber, said piston chamber having exhaust ports atfdiiierent positions and successively covered and uncovered by the pistoman automatic valve for distributing motive fluid to the piston, trip passageways for the valve leading from the piston chamber at different points and successively covered and uncovered by the piston, a sleeve journaled on the cylinder and controlling` one ofthe exhaust ports and one of the trip passageways, and a spring interposed bet-Ween the cylinder head and sleeve 5. In aI variable stroke fluid operated tool, the combination With a cylinder having a piston chamber, of a rear head for the cylinder threaded thereon, a piston in the piston chamber, said piston chamber having e1;- haust ports for the piston chamber at different positions and successively covered and uncovered by the piston, an automatic valve for distributing motive fluid to the piston, trip passageways for the valve leading from the piston chamber at different points 4and successivelyv covered and uncovered by the piston, a sleeve j'ournaled on the cylinder and controlling one of the exhaust ports and one of the trip. passageways, a spring interposed between the cylinder head and sleeve, and means pressed aga-inst by the spring for holding the piston head against rotation on the cylinder.

6.. In a variable stroke motor, the coinbination With a cylinder member having a piston chamber and a piston operating in the chamber, of an automatic distributing valve for controlling the delivery of motive fluid to the piston chamber to operate the, piston therein, means including supply ports open ing into the piston chamber at dierent points and uncovered successively by the piston for delivering fluid from the piston chamber-to the valve for shifting it, said cylinder member having an exhaust port open ing from the piston chamber between the sup ply ports and uncovered by the piston after one of saidA supply ports is uncovered and the other is covered by the piston, and means for closing the first supply port that is uncovered and closing said intermediate eX- haust port to cause the fluid to operate on the piston until the second supply port is uncovered. A

7. In a variable stroke motor, the combination with a cylinder member having a piston chamber and a pistonoperating in the chamber, of an automatic distributing valve for controlling the delivery of motive fluid to the piston chamber to operate the piston therein, means for delivering fluid from the piston chamber to the automatic valve for tripping the said automatic valve at diflerent points in the travel of the piston including a first and a second supply port opening into the piston chamber and successively uncovered by the piston on its travel in one direction, an exhaust port to atmosphere between the supply ports and uncovered by the piston after the first of the supply ports is uncovered and before the second is uncovered, and common means for closing the first supply port and the intermediate exhaust port.

8. In a variable stroke motor, the combination With a cylinder member having a piston chamber and a piston operating in the chamber, of an automatic distributing valve for controlling the delivery of motive fluid to the piston chamber to operate the piston therein, means for delivering fluid from the piston chamber to the automatic valve for tripping said automatic valve at different points in the travel of the piston including a first and a second supply port opening into the piston chamber and successively uncovered by the piston on its travel in one direc tion, a first exhaust port to atmosphere between the suply ports and uncovered by the piston after the first of the supply port-s is uncovered and before the second is uncovered, a second exhaust port uncovered by the piston after the second supply port is uncovered, and means for closing the first eX haust port.

9. In a variable stroke motor, the combination with a cylinder member having a piston chamber and a piston operating in the chamber, of an automatic distributing valve for controlling the delivery of motive fluid to the piston chamber to operate the piston therein, means for delivering fluid from the piston chamber to the automatic valve for tripping said automatic valve atl different points in the travel of the piston including a first and a second supply port opening into the piston chamber and successively uncovered by the piston on its travel in one direction, a first exhaust port to atmosphere between the supply ports and uncovered by the piston after the first of the supply ports is uncovered and before the second is uncovered, a second exhaust port uncovered by the piston after the second supply port is uncovered, and means for closing the iirst exhaust port and closing the irst supply port While leaving the second supply port and second exhaust port o en.

p10. In a variable stroke motor, the combination with a cylinder member having a piston chamber and a piston operating in the chamber, of an automatic distributing valve for controlling the delivery of motive iiuid to the piston chamber to operate the piston therein, means for delivering fluid from the piston chamber to the automatic valve for tripping said automatic valve at dierent points in the travel of the piston including a first and a second supply port opening into the piston chamber and successively uncovered by the piston on its travel in one direction, a first exhaust port to atmosphere between the supply ports and uncovered by the piston after the first of the supply ports is uncovered and before the second is uncovered, a second exhaust port uncovered by the piston after the second supply port is uncovered, and common means on the cylinder member for closing` the rst exhaust port and closing the first supply While leaving the second supply port and second exhaust port open.

In testimony whereof, I affix my signature.

HJALLIER C. GUSTAFSON. 

